/Engine/Source/Runtime/Core/Public/Unix/UnixPlatformMisc.h
Uses cpuid instruction to get the vendor string
CPU info bitfield     Bits 0-3    Stepping ID
    Bits 4-7    Model
    Bits 8-11   Family
    Bits 12-13  Processor type (Intel) / Reserved (AMD)
    Bits 14-15  Reserved
    Bits 16-19  Extended model
    Bits 20-27  Extended family
    Bits 28-31  Reserved
static uint32 GetCPUInfo()